Cathode-ray tube rebuilding device

ABSTRACT

A device for holding and rotating a cathode-ray tube upon a true axis during the rebuilding of the tube including self-aligning mandrel members driven by slack-free chains carrying a reinforced tube saddle, with automatic compensation for tube misalignment, and radial two-directional microadjustment tool-mounting means for renecking the tube and installation of a new electron gun.

United States Patent 1 13,594,059

{72] Invent r Hen y F- H01 2,304,714 12/1942 Stringer 316/28 7234 N. Claremont. Chicago, 111. 60645 2,917 357 12/1959 Nash ct al. 316/27 [2!] App No 8 .770 3,034,778 5/1962 Shaffer et a1. .4 269/142 [22] Fi1ed June 30, 1969 t Primary Examiner-John F. Campbell 45 P t t d l 7 t l I d Ln 6 y 20 19 I Assistant Examiner-Richard Bernard Lazarus Att0rneyHarbaugh and Thomas [54] CATHODE-RAY TUBE REBUILDING DEVICE 12 Claims, 12 Drawing Figs.

[52] US. Cl 316/28 1 1 I .1 ABSTRACT: A device for holding and rotating a cathode-ray [50] of Search 316/27, 28, tube upon a true axis during the b ildi f the tube indud- 21269/321 ing self-aligning mandrel members driven by slack-free chains carrying a reinforced tube saddle, with automatic compensa- [56] References Clted tion for tube misalignment, and radial two-directional UNITED STATES PATENTS 8/1933 Butler et al.

microadjustment tool-mounting means for renecking the tube and installation of a new electron gun.

PATENTED JUL20 I971 SHEEI 1 BF 2 INVENTOR HENRY F HOLZ ATTOR NEYS PATENTEUJULZOIBH 3 59 059 SHEET 2 OF 2 INVENTORI HENRY F HOLZ BY #amfluz 200 ATTORNEYS CATHODE-RAY TUBE REBUILDING DEVICE BACKGROUND OF THE INVENTION The rebuilding of cathde-ray tubes consists mainly of removing the electron gun and replacing it with a new electron gun which steps follow very closely those disclosed in Butler U.S. Pat. No. 1,920,528 as applied to electric light bulbs. The process consists of cutting off the'base of the bulb, removing the filaments, replacing new filaments and renecking, evacuating and rescaling the bulb. The patents Nos. 3,063,777and No. 3,404,933 of Trax and -Wudman, respectively, show methods of rebuilding electron tubes particularly cathode-ray tubes, but show little detail concerning the apparatus used.

One of the main problemsin this art as applied to larger tubes, such as cathode-ray tubes, is accurate alignment of the tube axially for true rotation so that the cutting operations, release of the vacuum and renecking operations can be conducted with sufficient precision, speed and accuracyto substantially reproduce a new tube. In some devices initial axial alignment can be obtained but during rotation of the tube in carrying out the process steps misalignment is inevitable and no steps are taken or means provided to correct the alignment. This results in breakage of the neck of the tube during the cutting operation, sudden release of the vacuum which can crack parts of the glass, ruin the phosphor coating, cause outof-roundness in the renecking process or spoilage due to over heating of parts of the neck.

Another factor which accentuates the problem of alignment is variation in the speed of rotation of the tube during the process steps. Since the cutting, melting and cooling ofthe glass neck depend upon the even application of forces, heat or cooling, to the peripheral surface of the tubular neck, any dwell time or stoppage of the rotary motion can result in breakage, overheating or other uneven application of these forces and an unsatisfactory product. Lastly, the means by which the forces are applied to the neck of the tube, such as the heating flame jets, must'be adapted to finite adjustment and easy manipulation to facilitate the overall process,

The known prior art devices of this type employ a tube saddle having relatively flexible support arms carried by a spindle mounted in ordinary bearings and driven by a chain sprocket. The combination of the flexible saddle, the radial play in the bearings and the slack in thedrive chain results in accentuation of the maladjustment of the tube in the saddle and an increase in rejected products. The instant invention has for'its objective the provision of means which singly or in combination overcome the drawbacks of the prior art devices.

SUMMARY OF THE INVENTION This invention concerns the provision of a tube-rebuilding device wherein the tube is kept in constant alignment and constant rotational speed during the steps of renecking, smoothing the rebuilt neck and installing the electron gun and any deviations in concentricity are automatically compensated or adjusted without manual adjustment of the parts. Means are provided to insure repeat accuracy in the manipu lation of the gas flame jets, and alignment of the new neck which are easy to use, conveniently located and adapted to reduce the time required to rebuild a tube.

More particularly the invention concerns the provision of rigiditied tube saddle, suspended from a top spindle carried by a self-centering bearing and a lower mandrel carried axially thereof by a lower self-centering bearing, both of which are driven from a common drive shaft through twin drive chains having intermediate idler sprockets'that are adjustable to remove essentially all of the slack in the drive system. Instead of having the heating flame jets mounted on opposite sides of the tube neck a pair of flame jets is provided mounted from a single bracket on one side of the tube neck. One of the jets is mounted for rotation on a vertical axis. The entire device is held by means of a support which is accessiblefrom three sides.

DESCRIPTION OF THE DRAWINGS An embodiment of this invention is shown in the drawings, wherein:

FIG. I is a perspective view of the apparatus;

FIG. 1A is a fragmentary cross-sectional view of an aligning mandrel;

FIG. 2 is a fragmentary side plan view of the top bracket and drive train;

FIG: 3 is a fragmentary cross-sectional view taken along the lines 3-3 of FIG. 2;

FIGS. 4, 4A and 4B are fragmentary cross-sectional views of a renecked tube base with a gun mount tool therein, showing the sequence of operations that take place during the installation of a new electron gun; i FIG. 5 is a fragmentary cross-sectional view of the top spindle;

FIG. 6 is a cross-sectional view taken along the lines 6-6 of FIG. I;

FIG. 7 is a fragmentary cross-sectional view of the renecking tool shown in FIG. 1;

FIG. 8 is a cross-sectional view taken along the lines 8-8 of FIG. 7; and I FIG. 9 is a cross-sectional view taken along thelines 9-9 of FIG. 1.

THE PREFERRED EMBODIMENT Referring to FIG. I the device is shown to comprise a floor base 10 which can be a fabricated steel plate. To this base is attached, by means of welding, the main support 12 having the lower spaced horizontal bracket arms 14 and I6 and the upper horizontal spaced bracket arms 18 and 20. The bracket 14-16 includes an appropriate spacer plate 22 at the outer end to form a box frame housing the lower .drive chain 24. Similarly the upper bracket l8-20-includes the spacer plate 26. The inner ends of the bracketsare attached to the upright support 12 in a manner to maintain this spaced relationship. The upper driver chain 28 is housed between the plates 18 and 20. The bottom bracket 14-16 is further rigidified by the tie support 30 extending between the end and the top of the plate 10. This structure, formed as it is of steel plate, provides a rigid U- shaped opening 32 for the manipulation of tools to do work on a workpiece.

A pair of spaced cleats 34 and 36, is attached to the inside wall of the support 12 between the spaced brackets. The top cleat 34 has a bore 38 through which the rotatable drive shaft 40 extends. The sleeve 42 encompasses the drive shaft 40 between the cleats and is affixed to both cleats by means of welding as indicated at 44. The drive shaft 40 connects through the coupling 46 and a suitable self-contained-reduction gear to the drive motor 48. The shaft 40 extends through the bracket 14 wherein it is suitably supported by the bearings 50 and 52, through the sleeve 42, in guided relationship and up to the bracket 16 where it is rotatably supported by the bearings 54 and 56. At an intermediate point with the bracket l4-l6 the shaft 40 is keyed to the first drive sprocket 58 and similarly within the bracket l8-20 the shaft 40 is keyed to the second or upper drive sprocket 60. The motor 48 is suitably mounted by means of the bracket plate 62 in an out-of-theway position under the lower bracket. The power cord for the device is indicated at 64 connected throughthe foot switch 66 havingthe angularly support switch button 68, to the motor 48. The foot switch 66 is movable about the surface of the base 10 to any convenient position for the operator.

The upper bracket has an intermediate reinforcing plate 70 extending longitudinally therein and affixed to both the bracket members 18 and 20. The lower bracket has the reinforcing plate 72. These plates are welded in place along the longitudinal axes of the brackets. On a side of each of the reinforcing plates 70 and 72, there is provided an idler sprocket indicated at 74 and 75 in FIG. 1. FIG. 3 shows the mounting for idler sprocket 74 carried by the plate 70 in the top bracket and also represents the mounting for idler-sprocket 75 in the bottom bracket. These idler sprockets are supported on a pair of threaded shafts such as the shafts 76 and 77 mounted in a vertical plane and extending from the plate 70.,Each sprocket can be moved outwardly or inwardly to adjust the tension on the drive chains 24 and 28. To illustrate the ends of the shafts 76 and 77 carry a pair of journals 78 and 79 by means of which the sprocket 74 is rotatably mounted on the axle 80. The shafts 76 and 77 are threaded and have the opposing lock nuts 81 and 82 in each side of the plate 70. Both the top and bottom of idler sprockets lie in the planes of the respective drive sprockets 60 and 58 as illustrated in FIG. 2.

The top bracket is suitably bored as at 86 to receive the spindle 88, carried therein by the self-aligning bearings 90 and 90' and passes through the driven sprocket 92 which engages the other end of the top drive chain 28. The shaft or spindle 88 can be reciprocated in the mounting to any desired position along its length and is then locked in position by means of the wingnut 94 which engages the shaft through the journal of the sprocket. This wingnut is large enough to be easily reached and turned by the operator.

The bottom bearing 90' carries the rotating drive sleeve 96 which extends through bracket 20 as part of the rotating journal of the driven sprocket 92. The lower end of the sleeve 96 is welded as at 97 to the top diametric arm 98 of the tube cradle or yoke 100 comprising having the integral downwardly depending arms 104 and 106 and the lower inwardly depending arms 108 and 110 all in the same plane. The spindle 88 extends through this assembly in a free slidable relationship. The cradle 100 is rotated through the rotation of the sprocket 92, but the spindle 88 can be moved and locked in various positions on the vertical axis. The cradle 100 is symmetrical and has the reinforcing corner cleats 114 and the formed comers 116 to provide a rigid support for the split-ring saddle 118 holding the illustrative vacuum tube 120.

At the bottom end of the spindle 88 there is provided the foot 122 having the hollow shank 124 (see FIG. into which the stub shaft 126 is affixed by means of the bolt 128. The shaft 126 extends beyond the peripheral edge 130 of the shank and is affixed to the spindle 88 as by means of the threads 129. A compression spring 132 is provided between the end of the spindle and the edge 130 of the shank. The head of the bolt 128 forms a stop since it is larger in diameter than the inside bore of the shank. The bottom end of the foot 122 is open and flared and provided with the flange 134 to retain the rubber pad 136. The pad and foot are biased downwardly and form a resilient mounting for engagement with the face of the tube 120. In this position the tube and spindle rotate together.

The bottom bracket l4-16 supports the bottom rod or mandrel 138 by means of the self-centering bearings 140 and 140', such bearings being held by means of suitable bolts, il- Iustrated. The top bearings 90 are similarly mounted to the brackets 18-20. These four bearings are self-centering and are preferably equivalent to' Browning type FB-2 l 0 bearings.

The lower drive chain 24 engages a lower driven sprocket like sprocket 92, affixed to the mandrel 138 between the bottom bearings. The arrangement is such that the lower driven sprocket has the integral sleeve 139 extending through the top bearing where it is releasably attached to the rod 138 as by means of a convenient wing nut 142, such as shown by the wingnut 94 in fig. 2. This allows the mandrel to be raised and lowered as desired. The mandril or rod 138 is centered and aligned with the spindle 88 and adopted to support any suitable aligning head or gun mount tool for the purpose of receiving the neck 143 of the tube 120 as the tube is initially placed in the saddle 118v One suitable aligning head tool 144 is shown in FIG. 1A here shown supported on rod 138 and engaging the cutoff neck 143 of a used tube. The head 144 is so dimensioned as to slidably engage the inside of the neck and the bore 145 of the head encompasses the end of the rod 138, both in a snug fit. These parts are all rotated simultaneously in the same direction and the rod is merely run up to engage the tool with the neck so that the tube is properly and immediately centered. The tool 144 is made of hard rubber or plastic and provided in various diameters to fit standard tube neck sizes.

The saddle 118 is centered in the yoke and has a series of asbestos pads 152 which engage the tapering tube wall 153 at circumferentially spaced points above the neck as illustrated in FIG. 6. This insulates the tube, which will become heated during the process, from the metal saddle ring 118. The slot 154 is wide enough to allowthe neck 142 to pass therethrough so that the tube wall can move downward into contact with pads.

Referring to FIG. 1 the tubular support arm 155 has the journal I56 affixed at one end and engaging the sleeve 42 in slidable relationship. The journal has the wing nut 158 for locking engagement of the journal to the sleeve 42 at any desired position therealong.

The support arm 155 carries the reciprocatable arm 160 in telescoping relationship and has the wingnut 162 to hold this arm in locked positions therealong. The arm 155 is shown to have a rectangular bore to receive the arm 160 having a rectangular cross section mating therewith. This prevents the arm 160 from turning with in the support arm 155. Other equivalent means can be used to maintain the slideable nonrotating relationship between these parts. The extended end of the reciprocatable arm 160 is provided with the channel 164 housing the rack 166 and has the opposing tabs 168 rotatably supporting the pinion gear 170 upon the shaft 172 and controlled by the knurled handwheel 174.

The upper end of the rack 166 is affixed to the manifold block 176 having the fuel lines 178 and 180 communicating through suitable passages to supply combustible gases to the jets.182 and 184. The jet 182 is fixed while the jet 184 is rotatably mounted and has the handle bar 186 for hand rotation or oscillation of this jet on a vertical axis. By this arrangement the jets can be positioned at any desired oint in relation to the tube neck 142. The relationship of these parts is better shown in FIG. 9 wherein the rotatable relationship of the jet nozzle 184 is shown by the arrow.

As one aspect of the invention there is provided the reneck tool 190 (shown in detail in FIGS. 7 and 8) comprising the inner tube 192 which slidably receives the shaft 194 having the elongated spline groove 196. The base collar 198 is adjustably affixed to the lower end of the tube 192 by means of the Allen screw 200 and carries the pin 202 the inner end of which slidably engages the spline 196. The spline 196 can be continuous as shown, along the length of the shaft 194 or terminate above the bottom end of the shaft asdesired. The shaft 194 has the coupler 204 engaged thereto by means of the Allen screw 206 and the bore 208 engages both the shaft 194 and the lower mandrel shaft 138. The Allen screw 209 holds the coupler to the shaft 138.

The upper end of the tube 192 carries the collar 210 having the lower flange 212 and provided with the radially spaced slots 217 communicating through the length of the collar. The collar 210 is press-fitted to the tube 192.

The tube 192 also carries the manifold 216 which normally rests upon the base collar 198, serving as a trust bearing therefor, and having the inner circumferential bore 218 which I is spaced from the exterior of the tube 192. At the bottom of the bore 218, there is provided the bronze sleeve bearing 220, press-fitted therein whereby the manifold 216 is rotatably mountedon the tube 192. The manifold has the radial bore 222 communicating with the central bore 218 above the bearing 220 and includes the threaded fitting 224 to which the flexible tube 226 is attached. The fixed collar 210 receives the rubber gasket 228, same being formed of a rubber stopper or the like. The gasket 228 is adapted to be inserted in sealed relationship into the new neck 240 to be installed into a tube after the old base has been removed, as will be described. Various sizes of the gasket or stopper 228 are used to fit the neck of each tube being repaired. The stopper 228 is frustoconical to readily receive the neck 240 and form a seal.

From this description it is apparent that the driven mandrel shaft 138 rotates all of the parts except the collar 216 or as the reneck tool 190 rotates the collar 216 and the tube 226 can be held stationary, while light air pressure is applied through the tube 226 into the bore 218 and into the slots 214 to pressure the inside 232 of the necks 143 and 240.

The initial operation in rebuilding a tube is a hand operation to sever the neck at the selected point and release the vacuum. To do this the operator brings a file into contact with the neck and makes a scratch. A loop of Crommel wire is placed around this scratch and a current of about 7 rVOltS is supplied from a filament transformer to the wire. This heats the wire rapidly and causes the glass neck to crack forming the severed edge 230 (see FIG. 1A). The vacuum is released slowly as air seeps through the very small circumferential cracks thus formed. This prevents any damage to the phosphor coating on the inner face of the tube. The base and the malfunctioning electron gun can now be removed from the neck of the tube. The cathode-ray tube 120 (FIG. 1) represents a tube which has had the base removed in this manner and is now ready to be rebuilt. The tube is inserted into the saddle 118 while both shafts 88 and 138 are retracted. The shaft 88 is moved downward until the shoe 122 presses lightly against the top or face part of the tube. The shaft 138 is moved upwardly with the aligning tool 144 thereon to receive the neck 143 of the tube in the manner shown in FIG. IA. The button 68 is pressed, both shafts are rotated simultaneously in the same direction and within a few revolutions the tube is centered exactly and rotates concentrically with the yoke.

The aligning tool 144 is removed and replaced by the renecking tool 190 on the lower mandrel shaft I38 in its lowered position. The proper size of reneck glass tube 240 is placed on the rubber gasket 228 and the entire assembly is raised up to a position about 'ginch from the severed neck 230 of the tube 120. A suitable source of a combustible gas is supplied through the tubes 178 and 180 and the jets lighted. The jets are adjustable to produce a soft flame for preheating the glass and means provided in the system to add oxygen to the combustion mixture to provide a sharp, hot conical flame to melt the glass. The gas jet assembly is manipulated and adjusted by means of the telescoping brackets H54 and 160 and the rack and pinion through manipulation of the knob I84. As the tube is rotated simultaneously with the reneck glass tube 240 the opposing spaced edges of the glass are heated, using a soft flame. The gas supply is gradually increased to full velocity and oxygen introduced to mix with the gas to form a hotter flame. The jets are moved to place the tips of the flame comes adjacent the opposed edges of the glass tubes. When the glass becomes white hot, the reneck tool is raised up slightly on the rod 192 by raising the manifold 216, as the tubes are rotating, far enough to join the edges together. Then the reneck tool is allowed to move back down to its original position and air is blown by mouth through the tube 226 into the inside of the neck to swell the glass to its original position. As the molten edges of the glass blend together, a piece of carbon slate is held on the upper portion of the neck of the tube to act as a guide against which the hot rejoined glass is formed into a true vertical plane with the balance of the unmelted glass. The motor drives the yoke at about 28 to 30 rpm. to accomplish a good seal, equivalent to a new neck on the tube, in less than one minute.

FIGS. 4, 4A and 4B illustrate the installation of a new electron gun while the renecked cathode-ray tube is still in position on the sealing machine. For this purpose the gun mount tool 244 is used comprising a stainless steel tube 246 provided with the bore 248 of a diameter such that it fits concentrically over the rod 138. The wing bolt 250 is used to affix the tool to the rod l38.-At the top of the tube 246 the bronze head 252 is attached thereto by means of an interference fit (heat shrinkage or press-fit). The head has the circumferential recess 254 and the flared or frustoconical tip 256 having a relative thin wall defining the space 258.

The new electron gun 260 to be installed is illustrative only and only a portion of the electrical components are shown, such as the multiple lead wires 262 that are sealed through the glass base 264 and extend along the outside of the glass tubu- Iation 266, that forms an integral part of the electron gun designed to be installed in a tube.

The bore 248 communicates with the space 258 and is sufficiently large to accommodate the tabulation 266 with the wircs within the annular space 268 therebetween. The glass base 264 is thus seated around its bottom outer edge upon the plate end 270 ofthe head 252.

The electron gun 260 is inserted into the new neck 240 to the desired position which will generally be below the seal line 230 formed during the process of renecking the tube. Then the gun mount tool 244 is inserted over the tubulation 246 and the wires 262 are guided into the annular space 268. The position of the gun mount tool and electron gun is then as represented in FIG. 4. The flames or welding fires 280 and 282 are adjusted to a position on the outside of the neck 240 opposite the glass base 264 and rotation of the assembly is begun. As the glass is heated the larger mass of brass 252 conducts heat away from the electron gun but the exposed periphery of the base 264 becomes heated. As the tube 240 reaches the melting point it collapses as shown in FIG. 4A and the flames 280 and 282 are directed inwardly by turning the jet I82 slightly with the handle 186 to keep the hottest part of the flames against the melting glass. As soon as a sealed juncturc is formed the lower end or excess of the tube 240 begins to drop away from its own weight. Then a very sharp cutting flame from the jet 184, illustrated in FIG. 48 by the flame 282 is lowered and brought to bear radially against the thin wall or any remaining glass flange from the seal opposite the annular recess 254 so that the excess tube or glass is cut away as shown. The tube is now ready to be removed from the sealing machine and placed in an exhaust oven for further processing.

Either or both of the jets I82 and 184 can be rotatably mounted. The drive sprockets 58 and 60 are the same diameter and the diameters of the driven sprockets are'the same so that the shafts 88 and 138 are driven at the same speed. If desired the drive shaft 40 can rotate at the same rate or at a different rate than the driven shafts by using pairs of sprockets with diflerent numbers of teeth. Such adjustments may be used to accommodate a wide variety of tube sizes that can be processed in the instant vacuum tube rebuilding device. A suitable mixing manifold and values (not shown) are used and connected between the gas supply tanks and the tubes 178 and 180 to supply a controlled combustible mixture of a hydrocarbon gas and oxygen to the jets I82 and 184.

What I claim is:

I. A device for rebuilding vacuum tubes comprising:

a. a stand having a vertical support with a pair of coplanar bracket arms extending therefrom in spaced relationship;

b. a drive shaft extending along said vertical support and having a pair of drive sprockets thereon, contiguous to said bracket arms;

c. a second pair of sprockets rotatably supported in axial alignment at the ends of said bracket arms;

d. said second pair of sprockets being supported'on self-centering bearings held by said bracket arms;

e. drive chains connecting between the top pair and the bottom pair of said sprockets;

. a rotating collar extending downward from the top bearing, said collar being connected to said top sprocket for rotation therewith;

g. a yoke member affixed to said collar having downwardly depending coplanar arms supporting a split-ring saddle on their lower ends, said saddle being substantially axially aligned with said top and bottom bearings;

h. a spindle rod extending through said top bearings and rotatablysupported thereby;

i. said spindle rod being axially reciprocatable through said rotating collar;

j. resilient shoe means on the lower end of said spindle rod;

k. a mandrel rod extending through said bottom bearings and rotatably supported thereby;

I. said mandrel rod being axially reciprocable through said bearings; and

m. means to adjustably affix said rods at selected distances from each other.

2. A device in accordance with claim 1 including:

a. an idler sprocket engaging one of said drive chains intermediate a pair of said sprockets; and

b. means to extend and retract said idler sprocket whereby said chain can be adjusted to remove slack.

3. A device in accordance with claim 1 including: a. a rotatable sleeve adjustably mounted on a vertical axis from said support;

b. a support arm extending from said sleeve;

. a second support arm telescoping from said first support arm;

. a bracket on the extended end of said second support arm;

. a combustible gas jet on said bracket; and

. means to raise and lower said gas jet in relation to said support arms. A device in accordance with claim 1 including:

a reneck tooladapted to be attached to said mandrel rod comprising;

b. a shaft having a longitudinally adjustable nonrotatable 6. A device in accordance with claim 1 in which:

said idler sprocket is rotatably mounted on a vertical shaft;

. said shaft being supported between a pair of threaded members extending through a wall of said bracket; and

. lock nuts engaging said threaded members on each side of said wall.

. A device in accordance with claim 3 including said gas jet mounting wherein:

. said vertical axis for said rotatable sleeve comprises a stationary support sleeve encompassing said drive shaft.

A device in accordance with claim 1 including:

a gun mount tool adapted to be attached to said mandrel rod comprising b. a hollow shaft;

. a head of heat conducting material at one end of said shalt having a concentric bore communicating with said hollow shaft defined by a conical wall adapted to support the base of an electron gun with the tabulation thereof within said hollow shaft.

A device in accordance with claim 8 wherein:

said head is provided with an outwardly facing recess below said conical wall.

0. A device for rebuilding vacuum tubes comprising:

a stand supporting a pair of bracket arms from one side in vertically spaced relationship;

. a drive shaft supported between said bracket arms on self-centering bearings, and adapted to be connected to motor drive means;

. driven members rotatably supported at the extended ends of said bracket arms on self-centerin g bearings;

. said driven members being operatively connected to said .drive shaft for rotation therewith in unison;

. axially aligned collar members extending in opposed relationship from said driven members;

a tube yoke affixed to the upper of said collar members, said tube yoke having spaced depending arms supporting a split-ring tube saddle;

. a spindle shaft reciprocatably mounted through said bearings and provided with a resilient padded foot member to engage the top face of a tube;

. a mandrel reciprocatably mounted in the lower of said collar members;

. means to affix said spindle and said mandrel at selected spaced distances from each other;

. an extendable bracket arm rotatablysupported by said stand;

gas jet nozzles supported in said bracket ark; and

means to move said nozzles into operable spaced tangential relationship to the axis of said spindle and said mandrel whereby to selectively heat the tubular glass base member of a vacuum tube suspended by said tube saddle and rotating with said yoke.

11. A device for rebuilding vacuum tubes in accordance with claim 10 including:

a gun mount tool means adapted to be carried on the upper end of said mandrel;

said gun mount tool having a longitudinal bore to receive the tubulation and lead wires of an electron gun base; and including a heat-conductive head member with a relatively thin-walled top edge to receive the glass base of an electron gun to be installed, said head member being of lesser diameter than the opening in the neck of a vacuum tube and having a circumferential recess below said top edge.

12. A device for rebuilding vacuum tubes in accordance with claim 10 including:

a renecking tool which includes manifold means rotatably mounted on a shaft adapted to be supported by said mandrel in sealed relationship within the bore of a glass base to be installed;

. said manifold means having a radial passageway communicating with a circumferential passageway in turn communicating with the inside of said glass base whereby air pressure can be applied to the inside of said glass base as same is rotated by said yoke member and heated by said gas jets. 

1. A device for rebuilding vacuum tubes comprising: a. a stand having a vertical support with a pair of coplanar bracket arms extending therefrom in spaced relationship; b. a drive shaft extending along said vertical support and having a pair of drive sprockets thereon, contiguous to said bracket arms; c. a second pair of sprockets rotatably supported in axial alignment at the ends of said bracket arms; d. said second pair of sprockets being supported on selfcentering bearings held by said bracket arms; e. drive chains connecting between the top pair and the bottom pair of said sprockets; f. a rotating collar extending downward from the top bearing, said collar being connected to said top sprocket for rotation therewith; g. a yoke member affixed to said collar having downwardly depending coplanar arms supporting a split-ring saddle on their lower ends, said saddle being substantially axially aligned with said top and bottom bearings; h. a spindle rod extending through said top bearings and rotatably supported thereby; i. said spindle rod being axially reciprocatable through said rotating collar; j. resilient shoe means on the lower end of said spindle rod; k. a mandrel rod extending through said bottom bearings and rotatably supported thereby; l. said mandrel rod being axially reciprocable through said bearings; and m. means to adjustably affix said rods at selected distances from each other.
 2. A device in accordance with claim 1 including: a. an idler sprocket engaging one of said drive chains intermediate a pair of said sprockets; and b. means to extend and retract said idler sprocket whereby said chain can be adjusted to remove slack.
 3. A device in accordance with claim 1 including: a. a rotatable sleeve adjustably mounted on a vertical axis from said support; b. a support arm extending from said sleeve; c. a second support arm telescoping from said first support arm; d. a bracket on the extended end of said second support arm; e. a combustible gas jet on said bracket; and f. means to raise and lower said gas jet in relation to said support arms.
 4. A device in accordance with claim 1 including: a. a reneck tool adapted to be attached to said mandrel rod comprising; b. a shaft having a longitudinally adjustable nonrotatable collar thereon; c. a manifold rotatably mounted on said shaft; d. said manifold having a passageway extending from a side to the top thereof; e. a rotatable collar on said shaft having an orifice passage registerable with the top end of the passageway in said manifold in all relative rotative positions thereof; and g. a gasket on said rotatable collar for sealing relationship with a reneck glass tube.
 5. A device in accordance with claim 4 in which: a. connector means are provided at the lower end of said shaft for attachment to said mandrel rod.
 6. A device in accordance with claim 1 in which: a. said idler sprocket is rotatably mounted on a vertical shaft; b. said shaft being supported between a pair of threaded members extending through a wall of said bracket; and c. lock nuts engaging said threaded members on each side of said wall.
 7. A device in accordance with claim 3 including said gas jet mounting wherein: a. said vertical axis for said rotatable sleeve comprises a stationary support sleeve encompassing said drive shaft.
 8. A device in accorDance with claim 1 including: a. a gun mount tool adapted to be attached to said mandrel rod comprising b. a hollow shaft; c. a head of heat conducting material at one end of said shaft having a concentric bore communicating with said hollow shaft defined by a conical wall adapted to support the base of an electron gun with the tabulation thereof within said hollow shaft.
 9. A device in accordance with claim 8 wherein: a. said head is provided with an outwardly facing recess below said conical wall.
 10. A device for rebuilding vacuum tubes comprising: a. a stand supporting a pair of bracket arms from one side in vertically spaced relationship; b. a drive shaft supported between said bracket arms on self-centering bearings, and adapted to be connected to motor drive means; c. driven members rotatably supported at the extended ends of said bracket arms on self-centering bearings; d. said driven members being operatively connected to said drive shaft for rotation therewith in unison; e. axially aligned collar members extending in opposed relationship from said driven members; f. a tube yoke affixed to the upper of said collar members, said tube yoke having spaced depending arms supporting a split-ring tube saddle; g. a spindle shaft reciprocatably mounted through said bearings and provided with a resilient padded foot member to engage the top face of a tube; h. a mandrel reciprocatably mounted in the lower of said collar members; i. means to affix said spindle and said mandrel at selected spaced distances from each other; j. an extendable bracket arm rotatably supported by said stand; k. gas jet nozzles supported in said bracket ark; and l. means to move said nozzles into operable spaced tangential relationship to the axis of said spindle and said mandrel whereby to selectively heat the tubular glass base member of a vacuum tube suspended by said tube saddle and rotating with said yoke.
 11. A device for rebuilding vacuum tubes in accordance with claim 10 including: a. a gun mount tool means adapted to be carried on the upper end of said mandrel; b. said gun mount tool having a longitudinal bore to receive the tubulation and lead wires of an electron gun base; and c. including a heat-conductive head member with a relatively thin-walled top edge to receive the glass base of an electron gun to be installed, said head member being of lesser diameter than the opening in the neck of a vacuum tube and having a circumferential recess below said top edge.
 12. A device for rebuilding vacuum tubes in accordance with claim 10 including: a. a renecking tool which includes b. manifold means rotatably mounted on a shaft adapted to be supported by said mandrel in sealed relationship within the bore of a glass base to be installed; c. said manifold means having a radial passageway communicating with a circumferential passageway in turn communicating with the inside of said glass base whereby air pressure can be applied to the inside of said glass base as same is rotated by said yoke member and heated by said gas jets. 